1. Field of the Invention
This invention relates to 3D target imaging using radar, and more particularly to the use of Barankin Estimation to generate 3D target information in a single radar pass.
2. Description of the Related Art
Target identification during reconnaissance or within the theater-of-battle has long been a topic of interest in remote sensing. In radar Automatic Target Recognition (ATR), two-dimensional synthetic aperture radar (2D SAR) image formation has been used to render target signatures that are processed by ATR for identification. Such images are a projection of three-dimensional targets into a 2D imaging plane, typically resulting in a sacrifice of target height information. ATR signature processing consists of 2D target signature feature analysis. Recovering the third dimension, target height, and introducing it into ATR methods should improve identification performance.
Recently, 3D target imaging using radar has received funding in order to improve situational awareness and target identification in the theater of battle. Traditional 3D imaging requires multiple radar passes, as in interferometry or stereo SAR. In interferometry, the multiple pass set consists of a sequence of individual passes that are flown almost identically to one another, during SAR imaging, differing only by platform altitude from pass to pass. The multiple pass set is processed jointly by an interferometric algorithm that exploits the height difference between the passes to derive target height information (M. Richards; A Beginners Guide to Interferometric SAR Concepts and Signal Processing—IEEE Aerospace and Electronics Systems magazine, Tutorial Issue IV, vol. 22, no. 9, p. 5-29, September 2007). In stereo SAR, a pair of passes is typical where the first pass is right or left looking during SAR imaging, and the second pass look direction is opposite the first pass. It is common for both passes to intersect the same navigation way-point at the middle of their respective SAR imaging periods. A stereo SAR algorithm then processes the image pair exploiting layover differences between the images to obtain target height information (M. Desai; Spotlight mode SAR stereo technique for height computation—IEEE Image Processing, Issue X, vol. 6, p. 1400-1411, October 1997).